Concentration of Credit Risk Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended	3 Months Ended	12 Months Ended	3 Months Ended	6 Months Ended
	Jul. 31, 2012	Jul. 31, 2011	Jul. 31, 2012	Jul. 31, 2012 Accounts Receivable	Jan. 31, 2012 Accounts Receivable	Jul. 31, 2011 Tech Data [Member]	Jul. 31, 2011 Tech Data [Member]
Concentration Risk [Line Items]
Unsecured revolving credit facility (in usd)	$ 400.0		$ 400.0
Total sales to the distributors Tech Data Corporation and its global affiliates ("Tech Data") relative to Autodesk's consolidated net revenue	23.00%	17.00%	22.00%			22.00%	23.00%
Percentage of gross accounts receivable accounted for by Tech Data				26.00%	21.00%